Supernovae are the Source of Dust in Early Galaxies

By Brian Koberlein - July 08, 2023 11:35 AM UTC | Extragalactic
Dust is the building block for much of the Universe, including the planet you were born on. But where did all this dust come from? New research using JWST shows large quantities of dust surrounding two Type II supernovae that detonated in a galaxy 22 million light-years away. The observations from JWST showed that each remnant contained more than 5,000 times the mass of Earth in dust. This helps explain why the earliest galaxies are filled with dust and young stars that exploded as supernovae.
Continue reading

Astronomers Map out the Radio Waves Coming From Large Satellite Constellations

By Brian Koberlein - July 07, 2023 11:42 AM UTC | Observing
You've heard that satellite constellations like Starlink are a problem for astronomers and their telescopes. Because the satellites are communicating with radio waves, they're also an issue for radio astronomers. A new study used the Low-Frequency Array to observe 68 Starlink satellites as they flew overhead. The telescopes could detect the "unintended electromagnetic radiation" emanating from electronics onboard the Starlink satellites. These could impact radio observations, and unlike visible light, the glare isn't coming from reflected light but emissions from the satellites themselves.
Continue reading

Did the Pulsar Timing Array Actually Detect Colliding Primordial Black Holes?

By Brian Koberlein - July 06, 2023 11:10 AM UTC | Black Holes
With last week's announcement of the gravitational wave background detected by timing arrays, the assumption was that these are the constant thrum of supermassive black holes orbiting each other. A new paper investigates whether these gravitational wave signals come from a much earlier time in the Universe and a much greater distance. Instead of relatively nearby supermassive black holes, could these be coming from primordial black holes interacting early on in the Universe?
Continue reading

The Early Universe Ran in Slow Motion

By Brian Koberlein - July 05, 2023 01:42 PM UTC | Cosmology
One of Einstein's predictions is that we should see time moving at different rates at different ages of the Universe. Researchers have confirmed this prediction out to half the age of the Universe using Type 1a supernovae as standard candles. Astronomers have gone much further back in time, observing quasars that sent out their light 12 billion years ago. Over this vast distance, time has slowed to a crawl, with every second experienced by those quasars taking five seconds from our perspective.
Continue reading

Gravitational Waves Can Be Gravitationally Lensed, and This Could Provide Another Way to Measure the Expansion of the Universe

By Brian Koberlein - July 04, 2023 10:16 AM UTC | Cosmology
Astronomers can never have enough ways to measure the expansion in the Universe, from nearby stars to distant quasars. A new study suggests another method might come from the growing catalog of gravitational waves detected by LIGO and other observatories. As two black holes merge in a distant galaxy, the gravitational waves could pass close to a massive cluster that would create a gravitational lens. Some of the waves would take different paths around the gravitational lens, allowing astronomers to measure the expansion rate of the Universe. Gravitationally lensed gravitational waves.
Continue reading

A Planet Was Swallowed by a Red Giant, But it Survived

By Brian Koberlein - July 02, 2023 11:00 AM UTC | Exoplanets
When our Sun runs out of hydrogen fuel in its core, it'll switch to burning helium and bloat up as a red giant. This will make it 100 times larger, gobbling up the inner planets and maybe even Earth. Maybe there's hope. Astronomers have found a planet orbiting a dying star that must have been swallowed up during that expansion phase. The star would have been 1.5 times bigger during the red giant phase than the planet's orbit. Being inside a red giant star doesn't lead to the inevitable death of a planet.
Continue reading

Astronomers Find the Fastest Spider Pulsar, Filling in the Missing Link in Their Evolution

By Brian Koberlein - July 01, 2023 12:05 PM UTC | Stars
Pulsars are rapidly spinning neutron stars which release blasts of radio waves with atomic clocklike accuracy. The fastest can be turning hundreds of times a second. But another class of pulsars turns agonizingly slowly in comparison, completing a rotation in hours. Astronomers have termed these "spider pulsars" because they have to feast on a binary companion star to slow down like this. Now researchers have discovered the fastest-turning spider pulsar, completing a rotation every 53 minutes, which fills in a gap in their observations.
Continue reading